Exam 2 - all CNs Flashcards
Vagus Nerve: function of the terminal ganglia
Terminal ganglia close to target tissues
- innervated by the vagus nerve are the parasympathetic efferents relay ganglia
inspiratory stridor means
high pitched sound during inspiration
Facial Nerve
nucleus associated with general sensory functional class
Nucleus of spinal tract of V
General Sensory Functions
Tactile sensations from
- skin of external ear,
- wall of external auditory meatus &
- outer surface of tympanic membrane
Bell’s Palsy:
prevalence
cause
acute or gradual onset?
characterized by (3)
- The most common disease affecting facial nerve
- •Often caused by herpes simplex virus
- •Acute onset
- •Characterized by
- paralysis of facial muscles,
- impaired corneal blink reflex, and
- hyperacusis
Bell’s Palsy is Most common disease affecting facial nerve and Often caused by herpes simplex virus. It has an Acute onset and is Characterized by paralysis of facial muscles, impaired corneal blink reflex, and hyperacusis (inability to tolerate normal sounds which seem abnormally loud)
action of inferior rectus muscle:
depression of the eye
where are the nuclei that serve the glossopharyngeal nerve?
Rostral Medulla
What foramen does the glossopharyngeal nerve pass through in the cranium?
The Glossopharyngeal nerve passes out of the cranium through the jugular foramen
(the superior and inferoir ganglia are also in the jugular foramen)
Whare are the nuclei that serve the vagus nerve located?
the medulla
what primary afferents ore the only CN V afferents that do not have their cell bodies in the trigeminal ganglion?
the 1° afferent cell bodies for proprioceptive information from muscles of mastication.
they synapse in the Mesencephalic Nucleus of the midbrain and rostral pons
Clinical evaluation of the Vestibulocochlear Nerve includes tests of: (3)
- –Ability to coordinate eye–head movements (vestibulo-ocular reflex)
- –Balance tasks
- –Hearing
Clinical evaluation of the vestibulocochlear nerve includes tests of: Ability to perform coordinated eye–head movements with movement of the head (vestibulo-ocular reflex), balance tasks and demonstrate appropriate hearing. We will discuss all of these test when we discuss the vestibular and auditory systems later in the course
RIN
Rostral Interstitial Nucleus
(of the midbrain reticular formation)
PPRF
Paramedian Pontine Reticular Formation
what does the abducens nerve innervate?
lateral rectus muscle
Glossopharyngeal nerve: where are the otic ganglion found?
suspended from mandibular nerve immediately below foramen ovale
list the types of functions carried in the vagus nerve:
- –General sensory
- –Special sensory
- –Branchial motor
- –Visceral motor
- –Visceral sensory (left off this diagram)
(the same 5 functions as the glossopharyngeal nerve)
Where is horizontal gaze coordinated?
Paramedian pontine reticular formation
CN number of Abducens Nerve
VI
Inferior rectus
Innervation:
primary action:
Innervation: Oculomotor (III)
primary action: depression
List the cranial nerve nuclei in pons and medulla related to the facial nerve (VII): (4)
Facial Nucleus
Solitary nucleus
Superior salivatory nucleus
Nucleus of the spinal tract of V
special sensory functions of vestibulocochlear nerve
- Vestibular information
- balance/equilibrium
- Cochlear information
- hearing/auditory
The vestibulocochlear nerve (CN VIII) Special sensory conveys Vestibular (balance/equilibrium) information from the vestibular organs of the inner ear and Cochlear (hearing/auditory) information also from the inner ear
Nucleus oralis:
location
transmits
one of three regions of spinal trigeminal nucleus
- Most rostral
- Transmits
- fine (discriminative) orofacial touch
what muscles should we palpate in clinical evaluation of the trigeminal nerve & locations?
what should we do while palpating?
–Masseter (A)
–Temporalis (B)
–Pterygoid (C)
have pt resist jaw opening during palpation
Glossopharangeal Nerve (IX): what is the purpose of the special sensory component?
–Special sensory – taste from the posterior one-third of the tongue
What is the pyriform cortex composed of?
The pyriform cortex is composed of the:
- Periamygdaloid cortex
- Anterior portion of parahippocampal gyrus ()
it is the primary olfactory cortex and locaed in the medial temporal lobe
meaning of dysarthria
hoarseness of speech
four steps in the initial portion of the primary pathway that starts with Olfactory mucosa:
- The surface of the olfactory mucosa is covered in mucus
- Sensory cells (bipolar) are imbedded in the mucus
- Axons from the sensory neurons collectively form the olfactory nerve & penetrate the cribriform plate of ethmoid bone
- The axons end on the mitral cells of the olfactory bulb
The receptor surface is the Olfactory mucosa which is Mucus covered. Sensory cells imbedded in mucus. Axons from these sensory cells collectively form olfactory nerve & each penetrates the cribriform plate of ethmoid bone. These axons End on mitral cells of olfactory bulb
There are olfactory tract projections to the following 6 cortical areas:
- Hypothalamus
- Orbitofrontal cortex
- Amygdala
- Hippocampus - (strong memories with odors)
- dorsomedial nucleus of thalamus (not shown)
- Limbic structures - (strong emotional reactions to odors)
Brainstem gaze centers:
function (general)
location
Function
- Coordination of conjugate eye movement
–Located in:
- Paramedian pontine reticular formation (PPRF)
- Rostral interstitial nucleus (RIN) of the midbrain reticular formation
What does the Ophthalmic nerve pass through when entering the scull?
Superior Orbital fissure
How are the axons leaving the trochlear nucleaus unqiue? (2)
- they decussate and innervate the contralateral superior oblique muscle
- Trochlear nerve is the only cranial nerve to exit the dorsum of the brainstem
Glossopharyngeal nerve (IX): What is the general sensory function?
–General sensory –
tactile sensation from the tonsils, the pharynx, the middle ear and the posterior 1/3 of the tongue
What type of functions does vestibulocochlear nerve have?
special sensory
Olfactory G-protein receptor cells:
receptor activation
- G-protein activates adenylate cyclase and cAMP production
- cAMP 0pens ion channels in the cell membrane, resulting in Na+ & Ca++ influx & Cl- efflux
- This causes depolarization- AP generation
Olfactory Receptor activation produces G-protein activation of adenylate cyclase and cyclic AMP production. The cyclic AMP Opens ion channels in the cell membrane, resulting in Na+ & Ca++ influx & Cl- efflux – the resulting influx of positive ions and efflux of negative ions produces a Depolarization and action potential generation
Glossopharyngeal nerve: what type of neurons does the nucleus ambigous have?
somatic motor: lower motor neurons which innervates the stylopharyngeus muscle
how can you clinically evaluate the integrity of the accessory nerve?
its integrity is tested using manual muscle testing against resisted
- head turning and
- shoulders shrugging
what is the spinal trigeminal tract?
first degree afferent axons from CN V that go either ascending or descending to 2nd degree neurons in the: nucleus of the spinal tract of V (spinal trigeminal nucleus)
(the words under Dr. Lake’s powerpoint says it could be to the mesencephalic trigeminal nucleus, or the cheif trigeminal nucleus too, but that is not what other sources say. I also emailed Dr. Lake and he replied that it is just the spinal trigeminal nucleus!)
where are the nuclei that serve the Accesory Nerve located?
- Medulla–
- Nucleus ambiguus
- Cervical Spinal Cord–
- Cervical ventral horn
The cranial portion arises from the Nucleus ambiguus of the medulla and the spinal portion arises from motor neurons of the upper Cervical ventral horn. The Cervical ventral roots rise through the foramen magnum to join with the cranial portion.
Together both portions exits thru jugular foramen
sensory test for fine touch and pin prick to face
will be discussed later with somatosensory systems
Inferior Oblique
Innervation:
primary action:
Innervation: Oculomotor (III)
primary action: Extorsion
list the functions of the visceral motor portion of the Vagus Nerve:
Visceral motor includes the
- parasympathetic innervation of the organs of the Thoracic & abdominal viscera
how does a jaw jerk reflex test work?
what are the afferent & efferent limbs?
what nuclei are invovled in the reflex?
- tapping of the jaw produces reflex contraction of the muscles of mastication
- –Afferent & efferent limb mandibular V3
- –Both thru mesencephalic & motor nucleus of V
The three most common sources of injury to the Oculomotor nerve (CN III) or Trochlear nerve (CN IV)
- –Inflammation of meninges
- –Aneurysms of internal carotid artery or other circle of Willis arteries
- –Swelling in brain with increased venous pressure in cavernous sinus
what nucleus gives rise to our sensation of jaw poistion and is the afferent limb in reflexes like the jaw jerk reflex?
Mesencephalic Nucleus of the midbain and rostral pons
Vagus Nerve: function of nucleus soitarius
–Nucleus solitarius –
visceral sensory afferents
definition of branchial
Medical Definition of BRANCHIAL. : of or relating to the gills or to parts of the body derived from the embryonic branchial arches and clefts.
function of the lateral rectus muscle
ocular (eye) abduction
(hence name “abduc - ens”)
what is the nuclear complex or nucleus serving the abducens nerve?
Abducens nucleus
(located in caudal pons)
How many extraocular muscles are there?
6
What is the complex and/or nuclei that serve the trochlear nerve?
Trochlear nucleus
in midbrain caudal to oculomotor complex
Is there just one spot in the brain that will affect conjugate eye movement if damaged?
No. loss of conjugate eye movement can result from damage to more than one brain region.
Function of superior oblque muscle:
intorsion (medial rotation)
what is the pyriform area?
primary olfactory cortex of medial temporal lobe – pyriform area
. where the axons of the mitral cells primarily end
What makes up the oculomotor nuclear complex? (2)
- Oculomotor nucleus (LMN with somatic motor function)
- Edinger-Westphal nucleus (parasympathetic prganglionic neurons with visceral motor function)
what does olfactory projections to the hippocampus do?
Hippocampus – strong memories with odors
what is the difference between nociception and pain?
Physiologists distinguish between pain and nociception; where
- nociception refers to signals arriving in the central nervous system resulting from activation of specialized sensory receptors called nociceptors that provide information about tissue damage.
- Pain then is the unpleasant emotional experience that usually accompanies nociception.
http://cell.uchc.edu/pdf/fein/nociceptors_fein_2012.pdf
What is conjugate movement?
- Coordinated movment of the eyes to maintain normal vision
- Requires cooperation of different CNs
- Eyes move together with great precision
Vagus Nerve: function of the Spinal Nucleus of V
–Spinal Nucleus of V –
somatic sensory (somatosensory afferents)
what are the parasympathetic nuclei of the brainstem that olfactory projections go to
the parasympathetic nuclei of brainstem
- Superior & inferior salivatory nuclei – salivation to pleasant odors
- Dorsal motor nucleus of vagus – nausea and vomiting to unpleasant odors
Projections to the Hypothalamalamic neurons which in turn have projections to parasympathetic nuclei of brainstem. Projections to the Superior & inferior salivatory nuclei – salivation to pleasant odors and to the Dorsal motor nucleus of vagus – nausea and vomiting to unpleasant odors
What is the purpose of the visceral motor component of the glossopharyngeal nerve (IX)?
–Visceral motor – parasympathetic innervation of the parotid gland (preganglionic to otic ganglion)
describe the Palthway of the nerve branches of facial nerve
- –Full nerve leaves pontomedullary junction
- –It Passes thru internal acoustic meatus with CN VIII
- –then Enters facial canal where geniculate ganglion found
- –the Parasympathetic fibers then split off to form greater petrosal nerve and synapse in pterygo-palatine ganglion in the pterygo-palatine fossa
- –the Sensory & motor branches pass thru stylomastoid foramen
The specific path of the facial nerve involves the Full nerve leaving the brainstem at the pontomedullary junction and passing thru internal acoustic meatus with CN VIII to Enter the facial canal where geniculate ganglion is found.
Parasympathetic fibers then split off to form the greater petrosal nerve which synapse in pterygo-palatine ganglion in the pterygo-palatine fossa
General sensory & motor branches pass through stylomastoid foramen
action of superior rectus muscle:
elevation of eye
What does the hypglossal nerve innervate?
the intrinsic & extrinsic tongue muscles
action of medial rectus muscle:
adduction of eye
two things commonly tested in clinical evaluation of the facial nerve
- •Special sensory –
- taste (salty, sweet or sour)
- •Branchial motor
- –Make facial expressions
- –Observe for asymmetries
Facial nerve: What nucleus is associated with the special sensory functions
gustatory division of the solitary nucleus
What does the trochlear nerve innervate?
superior oblique muscle
what is the only division of the trigeminal nerve that contains motor function?
Mandibular (V3)
Glossopharyngeal nerve (IX): superior ganglion contains what kind of cell bodies?
–Superior ganglion –
somatic afferents (cell bodies of somatic primary afferent fibers)
meaning of dysphagia
Difficulty with swallowing
Movment of eyes to right requires the activation of which muscles?
left medial rectus (oculomotor nerve, III)
right lateral rectus (abducens nerve, VI)
Vagus Nerve: function of the inferior ganglion
Inferior ganglion –
- visceral & special sensory afferents
action of inferior oblique muscle:
extorsion (lateral rotation)
Facial nerve number
CN VII
name of cranial nerve I:
olfactory nerve
nucleus caudalis:
location
Transmits
one of three regions of spinal trigeminal nucleus
- Most caudal
- transmits:
- orofacial nociception
- thermal sensations
draw the facial nerve chart
what is the number for the Glossopharyngeal Nerve?
IX
Glossopharyngeal nerve (IX): Inferior ganglion contains what kind of cell bodies?
–Inferior ganglion –
visceral & special sensory (cell bodies of the visceral & special sensory primary afferent fibers)
what type of function does the Abducens Nerve have?
Somatic Motor
What cranial nerves innervate the extra-ocular muscles?
III (somatic motor component)
IV
VI
Oculomotor (III)
Trochlear (IV)
Abducens (VI)
Where is vertical gaze controlled?
Rostral interstitial nucleus (RIN)
What Connects the PPRF and RIN to oculomotor lower motor nuclei?
Ascending medial longitudinal fasciculus (MLF)
Clinical Evaluation of the Facial Nerve: Special sensory
taste with one or more of the following:
- salty
- sweet
- sour
list the nuclei that serve the vagus nerve (4)
- –Nucleus solitarius –
- visceral sensory afferents
- epiglottic taste - gustatory portion
- –Dorsal motor nucleus of X –
- visceral motor preganglionic parasympathetic efferents
- –Spinal Nucleus of V –
- somatic sensory (somatosensory afferents)
- –Nucleus ambiguus –
- branchial motor to the pharyngeal and laryngeal musculature